• 대한소아치과학회지
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• 제26권2호
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• pp.377-398
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• 1999

불소도포시 주로 형성되는 calcium fluoride는 구강내 환경에서 pH에 의해 조절되는 불소의 저장고 역할을 하여 치아우식 예방에 있어서 중요한 역할을 하는 것으로 알려져 있다. 따라서 불소도포의 우식예방 효과는 calcium fluoride를 얼마나 많이 형성시켜 오래 지속시키는 가에 달려 있다. 이에 치아 내산성 증가에 효과 있다고 알려진 Nd:YAG 레이저 조사가 calcium fluoride형성 및 치아 내산성에 미치는 영향에 대해 알아보기 위해서 실험을 시행하였다. 소의 영구전치에서 276개의 시편을 제작하여 아무런 처치를 하지 않은 군을 대조군으로 하고 1.23% acidulated phosphate fluoride (APF) 5분, 30분 도포 및 Nd:YAG 레이저 조사에너지 밀도 $20J/cm^2,\;40J/cm^2$의 조건에 따라 불소 도포군, 레이저 조사군, 불소 도포후 레이저 조사군, 레이저 조사후 불소 도포군으로 분류하였다. 불소도포를 시행한 경우 이를 다시 KOH 처리 여부에 따라 나누어 23개의 실험조건을 만들었다. 각 실험조건에 12개의 시편을 배정하고 이중 10개의 시편은 불소 및 무기인 측정에, 나머지 2개의 시편은 표면 관찰에 사용하였다. KOH 비처치군에서 0.1 N HClO4로 enamel biopsy를 시행하여 탈회 법랑질의 불소농도 및 탈회깊이를 측정하였으며 KOH 처치군에서는 1 M KOH로 24시간 처리하여 calcium fluoride를 정량 후 enamel biopsy를 시행하였다. 실험결과 얻어진 자료 및 주사 전자현미경 관찰 소견을 비교하여 다음의 결과를 얻었다. 1. KOH 비처치군에서 탈회된 법랑질의 불소농도는 레이저조사 후 불소도포시 레이저 에너지 밀도 증가에 따라 증가되는 경향을 보였다. 2. KOH 비처치군에서 법랑질 탈회깊이는 불소를 5분 도포후 레이저 $20J/cm^2$를 조사한 경우를 제외하고는 레이저와 불소를 병행하여 처치시 각각을 단독으로 처치시보다 탈회깊이가 작았다 (p<0.05). 3. Calcium fluoride의 양은 레이저의 조사에 의해 유의 있게 증가하지 않았다 (p>0.05). 4. Calcium fluoride 입자는 불소만 도포한 경우에 비해 레이저 조사후 불소도포시 입자크기가 증가되었으며, 불소도포후 레이저 조사시 입자크기의 증가와 함께 일부 융합된 양상을 보였다. 5. KOH 처치군에서 법랑질의 불소농도는 불소를 30분 도포후 레이저를 조사한 경우를 제외하고는 대조군의 불소농도와 유의한 차이가 없었다(p>0.05). 6. KOH 처치군에서 불소와 레이저를 병행한 경우, 불소만 도포한 경우보다 탈회된 법랑질의 깊이가 작았다 (p<0.05). 7. KOH 비처치군에서 탈회된 법랑질의 불소농도와 탈회깊이의 상관관계(Spearman correlation coefficient: -0.6281)는 KOH 처치군(Spearman correlation coefficient: -0.3792)에 비해 높은 음의 상관 관계를 보였고, 동일한 조건으로 불소도포 및 레이저 조사를 시행한 경우에 있어서 KOH 처리 여부에 따른 탈회법랑질 깊이의 유의차가 있는 경우 calcium fluoride의 형성량이 많았다. 이상의 실험결과로 미루어 보아 레이저 조사가 calcium fluoride의 형성량에 영향을 미치지 않았으나 레이저 조사의 영향으로 calcium fluoride의 용해가 감소하는 것으로 판단된다. 또한 불소도포 및 레이저 조사의 병행은 각각을 단독으로 처치한 경우에 비하여 치아 내산성 증가면에서 유리하므로 임상에서 불소도포주기 연장과 같은 유용한 결과를 얻을 수 있을 것으로 생각된다.

• Journal of Periodontal and Implant Science
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• 제38권1호
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• pp.67-74
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• 2008

Purpose: The aim of this study was to evaluate the effect of Er:YAG laser on microstructure and roughness of $TiO_2$ blasting implant surface. Materials and Methods: Ten $TiO_2$ blasting implant were used in this experiment. One implant was control group, and nine $TiO_2$ blasting implant surfaces were irradiated with Er:YAG laser under 100 mJ/pulse, 140 mJ/pulse, and 180 mJ/pulse condition for 1 min, 1.5 min, and 2 min respectively. Optical interferometer and scanning electron microscopy was utilized to measure roughness and microstructure of specimens. Results: The surface roughness was decreased after Er:YAG laser irradiation in all groups, but there was no significant difference. 100 mJ/pulse and 140 mJ/pulse group did not alter the $TiO_2$ blasting implant surface in SEM study while 180 mJ/pulse group altered the $TiO_2$ blasting implant surface. Implant surfaces showed melting, microfracture and smooth surface in 180 mJ/pulse group. Conclusion: Detoxification of implant surface using Er:YAG laser must be irradiated with proper energy output and irradiation time to prevent implant surface alteration.

• 대한소아치과학회지
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• 제29권4호
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• pp.600-606
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• 2002

본 연구는 레이저 형광을 치아의 교합면에 적용하여 임상에서 초기 교합면 우식증의 감별에 레이저의 이용가능성을 평가하는데 그 목적이 있다. 아르곤 레이저 형광법의 교합면 우식증 탐지효과를 평가하기 위해 발거된 사람 치아 중에서 치아우식증을 제외한 결함이 없고 법랑질이 건강한 대구치와 소구치 50개를 선정하여 시진, 탐침을 이용한 시진, 아르곤 레이저 형광법을 이용해 관찰한 결과와 편광현미경으로 관찰한 병소의 깊이를 비교하여 다음과 같은 결론을 얻었다. 1. 교합면 우식의 조직학적 깊이와 아르곤 레이저 형광법에 의한 교합면 우식증 평가법과 시진, 탐침을 이용한 시진사이에서 모두 높은 상관 관계를 보였다. 2. 교합면 우식증의 조직학적 깊이와 각 검사법간의 일치도(kappa치)는 각각 시진이 0.189, 탐침을 이용한 시진이 0.128, 레이저 형광법이 0.472 이었으며, 레이저 형광법이 가장 일치도가 높았다. 이상의 결과를 종합해 보면 육안적 검사보다는 레이저 조사 후 관찰된 우식과 편광현미경상에서의 우식이 더 유의성 있는 관계를 보여 교합면 우식증탐지에의 레이저 형광법의 적용이 가능하리라 사료된다.

• Restorative Dentistry and Endodontics
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• 제22권1호
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• pp.479-489
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• 1997

The purpose of this study was to evaluate the effect of the Nd : YAG laser on the tooth hypersensitivity by the observation of the morphological changes of the dentinal surface irradiated with Nd : YAG laser by use of SEM. In 40 mandibular and maxillary molars without any carious lesion or restoration, severe attrition and abrasion, Enamel was removed with fine grit diamond bur and exposed dentinal surfaces were polished with Soflex discs. In control group (10 teeth), exposed dentinal surfaces were acid-etched with 10 % Maleic acid for 15 seconds. In the experimental group 1 (10 teeth), acid-etched dentinal surfaces with 10% Maleic acid were prepared by Nd : YAG laser (6 watts power, 1 psi water, 18 psi air) for 2 minutes. In the experimental group 2 (10 teeth), exposed dentinal surfaces were irradiated with Nd: YAG laser (10 watts power, 3 psi water, 10 psi air) until the painted black stains on the dentinal surfaces were completely removed. In the experimental group 3 (10 teeth). dentinal surfaces were prepared with Nd : YAG laser (6 watts power, 1 psi water, 18 psi air) until the painted black stanins on them were completely removed and then the irradiated dentinal surfaces were acid-etched with 10 % Maleic acid for 15 seconds. The specimens were routinely processed and observed with scanning electron microscope. The results were as follows : 1. In the irradiated dentinal surfaces, the characteristics of the melting and recrystalization on the dentinal surfaces were observed. Compared with the results in the control group, we could observe that in the irradiated dentinal surfaces, the aperture of the dentinal tubules were reduced and there were more debris obstructing the dentinal tubules. 2. In the irradiated dentinal surfaces, crater structures were commonly present and in the crater bottoms, there were a lot of bead like melted dentin structures, which had the ruptured opening in the center of them. 3. The melted dentins and cracks in the smear layer were less frequently observed in the irradiated dentinal surfaces using copious cooling water than in the irradiated dentinal surfaces using scare cooling water.

• Restorative Dentistry and Endodontics
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• 제26권4호
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• pp.307-315
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• 2001

The application of Nd:YAG laser and irrigants to the root surface can change its surface configurations. The purpose of this study was to investigate the effects of Nd:YAG laser and irrigants on the apical seal of obturated canals. In this study, 66 single rooted teeth were randomly assigned to 4 group of 14 teeth each. 8 teeth were served us positive and negative controls. The teeth were divided into 6 groups as follows. Group A: Nd:YAG laser, 5% NaOCl + Rc-prep Group B: Nd:YAG laser, Saline Group C: 5% NaOCl + Rc-prep Group D: Saline Group E: Positive control Group F: Negative control 66 teeth were instrumented using Maillefer ProFile$^{\circledR}$ (Orifice Shapers, .04 taper, .06 taper Dentsply, Switzerland). Two of each group were selected at random, and the canal wall surfaces were examined under a SEM. 12 teeth of each group were obturated using by lateral condensation technique. Specimens were immersed in india ink for 7days, decalcified by 10% nitric acid, dehydrated by 75. 80. 85, 90, 95 and 100% alcohol in order cleared by methyl salicylate and then measured of dye penetration with stereomicroscope($\times$15 magnification) and Image Pro plus. The data were analyzed statistically by one-way ANOVA test and Duncan's Multiple Range test. The results were as follows : 1. The mean leakage was 0.128$\pm$0.376 for group A, 0.237$\pm$0.325 for group B, 0.397$\pm$0.468 for group C, 0.586$\pm$0.402 for group D, and there were statistically significant differences between group A and group D, group B and group D. (p<0.05). 2. Group A had better sealing ability than Group C, but there was statistically no significant differences. (p>0.05). 3. Group B had better sealing ability than Group D and there was statistically significant difference. (p<0.05). 4 Group A had better sealing ability than Group B, but there was statistically no significant difference. (p>0.05). 5. Group C had better sealing ability than Group D, but there was statistically no significant difference. (p>0.05). 6. As a result of observation under SEM, Smear layers were removed in Group A, B. but Smear layers were partially removed and smear plugs were remained in Group C, Smear layers were not removed in Group D. To be specially, Melting of smear layer were showed in Group C. 7. These results suggests that the laser has a potential in reducing the apical microleakage of obturated canals.

• Journal of Periodontal and Implant Science
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• 제32권2호
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• pp.303-314
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• 2002

This study was performed to evaluate the usability of Er:YAG laser for periodontal therapy. Forty dental root slabs ($5{\times}5{\times}2mm^3$) were prepared from human periodontally diseased extracted teeth and grouped into 4 groups: 1) control (root planing only), 2) root planing and irradiated with laser at 30mJ, 3) root planing and irradiated with laser at 60mJ, and 4) root planing and irradiated with laser at 100mJ. The root slabs were embedded in resin block before laser treatment. Er:YAG laser was irradiated under water irrigation with the tip held perpendicular to the root surface in contact mode. After Er:YAG laser irradiation or planing on the root surface, morphological changes have been observed under SEM, and the micro-hardness and Ca/P ratio were compared. 1. In the Control group, the root surface showed the directional change caused by root planing instrumentation, and the presence of smear layer, and no exposure of dentinal tubule was observed. Laser irradiated group showed surface changes with rough dentin surface of niche and depression and dentinal tubule exposure by the elimination of smear layer. 2. The micro-hardness of root surface in the laser irradiated group was higher than the control group. The higher energy output was applied, the higher micro-hardness on root surface was resulted. 3. The higher energy output was applied, the higher Ca/P ratio was observed. The higher Ca/P ratio in 60mJ group and 100mJ group was statistically significantly compared to the control group and the 30mJ group. These results suggest that Er:YAG laser irradiation on the periodontally diseased root surface could remove smear layer and increase the micro-hardness on root surface and Ca/P ratio which contribute to enhance the acid resistance of periodontally treated root surface.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8383-8386
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• 2016

Background: To evaluate the safety, convenience and effectiveness of 940nm diode laser for treatment of homogenous leukoplakia. Materials and Methods: Ten patients having homogenous leukoplakia which were diagnosed clinically were selected from an Indian dental educational institution for the study. Toludine blue staining was applied locally over the lesion. The area where there was increased uptake of stain was excised using a 940 nm EZLASE TM diode laser (BIOLASE-USA). Results: Although various treatment modalities have been tried and the search continues for novel treatment modalities for complete removal of homogenous leukoplakia, from results of our preliminary pilot study it is clear that the use of 940 nm diode laser as a treatment modality for homogenous leukoplakia is a good substitute. Healing was perfect without any complication within a duration of 1 month. Pain intensity was also mild and absolutely zero on the VAS scale after 1 month follow up. Conclusions: 940 nm diode lasers are safe and can be effectively used as a treatment modality of homogenous leukoplakia, without any complication and without compromising health and oral function of patients. Considering recurrence factor, long term follow up for patients is a must.

• The Journal of Advanced Prosthodontics
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• 제6권2호
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• pp.88-95
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• 2014

PURPOSE. The purpose of this study is to evaluate if pre-treatment with desensitizers have a negative effect on microtensile bond strength before cementing a restoration using recently introduced self-adhesive resin cement to dentin. MATERIALS AND METHODS. Thirty-five human molars' occlusal surfaces were ground to expose dentin; and were randomly grouped as (n=5); 1) Gluma-(Glutaraldehyde/HEMA) 2) Aqua-Prep F-(Fluoride), 3) Bisblock-(Oxalate), 4) Cervitec Plus-(Clorhexidine), 5) Smart protect-(Triclosan), 6) Nd:YAG laser, 7) No treatment (control). After applying the selected agent, RelyX U200 self-adhesive resin cement was used to bond composite resin blocks to dentin. All groups were subjected to thermocycling for 1000 cycles between $5-55^{\circ}C$. Each bonded specimen was sectioned to microbars ($6mm{\times}1mm{\times}1mm$) (n=20). Specimens were submitted to microtensile bond strength test at a crosshead speed of 0.5 mm/min. Kolmogorov-Smirnov, Levene's test, Kruskal-Wallis One-way Analysis of Variance, and Conover's nonparametric statistical analysis were used (P<.05). RESULTS. Gluma, Smart Protect and Nd:YAG laser treatments showed comparable microtensile bond strengths compared with the control group (P>.05). The microtensile bond strengths of Aqua-Prep F, and Cervitec Plus were similar to each other but significantly lower than the control group (P<.05). Bisblock showed the lowest microtensile bond strength among all groups (P<.001). Most groups showed adhesive failure. CONCLUSION. Within the limitation of this study, it is not recommended to use Aqua-prep F, Cervitec Plus and Bisblock on dentin when used with a self-adhesive resin cement due to the decrease they cause in bond strength. Beside, pre-treatment of dentin with Gluma, Smart protect, and Nd:YAG laser do not have a negative effect.

• Restorative Dentistry and Endodontics
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• 제39권3호
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• pp.180-186
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• 2014

Objectives: The purpose of this in vitro study was to evaluate the microleakage and penetration of fissure sealant in permanent molar teeth with fluorosis after pretreatment of the occlusal surface. Materials and Methods: A total of 120 third molars with mild dental fluorosis were randomly divided into 6 groups (n = 20). The tooth surfaces were sealed with an unfilled resin fissure sealant (FS) material. The experimental groups included: 1) phosphoric acid etching (AE) + FS (control); 2) AE + One-Step Plus (OS, Bisco) + FS; 3) bur + AE + FS; 4) bur + AE + OS + FS; 5) Er:YAG laser + AE + FS; and 6) Er:YAG laser + AE + OS + FS. After thermocycling, the teeth were immersed in 0.5% fuchsin and sectioned. Proportions of mircoleakage (PM) and unfilled area (PUA) were measured by digital microscope. Results: Overall, there were significant differences among all groups in the PM (p = 0.00). Group 3 showed the greatest PM, and was significantly different from groups 2 to 6 (p < 0.05). Group 6 showed the lowest PM. Pretreatment with Er:YAG with or without adhesive led to less PM than bur pretreatment. There were no significant differences among groups in PUA. Conclusions: Conventional acid etching provided a similar degree of occlusal seal in teeth with fluorosis compared to those pretreated with a bur or Er:YAG laser. Pretreatment of pits and fissures with Er:YAG in teeth with fluorosis may be an alternative method before fissure sealant application.

• 대한치과교정학회지
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• 제52권6호
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• pp.399-411
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• 2022

Objective: The objective of this randomized clinical trial was to study the skeletal and dental effects of low-level laser therapy (LLLT) along with a miniscrew-assisted expander (Hyrax) after six months of retention. Methods: After sequence generation, concealed allocation, and implementation, 24 female patients were randomly divided (1:1) into two-groups: bone-borne rapid palatal expansion (BBE) without LLLT (n = 12) and BBE with LLLT (n = 12). Eligibility criteria included female patients aged 10-13 years old with bilateral posterior crossbites. Intraoral and extraoral photographs, cone-beam computed tomography images, and digital study models were obtained before expansion and six months after retention. The 7 mm Hyrax appliance was anchored to four palatal mini-screws, which were activated twice daily for 15 days, then locked and kept in place as a retainer. LLLT was performed in the laser group during expansion and retention, according to the guidelines provided. Results: The records of 24 patients were analyzed. According to the post-retention measurements, both groups showed a significant increase in nasal and maxillary widths and total facial height. In the laser group, the Sella-Nasion-Point A and Point A-Nasion-Point B angles and the interpremolar apical distance were significantly increased. Conclusions: Within the limitations of this study, the results suggest that the parameters and protocol of LLLT do not clinically affect the efficiency of BBE in prepubertal and pubertal patients.